Inspection

9 Inspect the selector forks for any signs of wear or damage, especially around the fork ends where they engage with the groove in the pinion. Check that each fork fits correctly in its pinion groove. Check closely to see if the forks are bent. If the forks are in any way damaged they must be renewed.

10 Measure the thickness of the fork ends

and compare the readings to the specifications at the beginning of this Chapter (see illustration). Renew the forks if they are worn beyond their specifications.

11. Check that the forks fit correctly on their shaft. They should move freely with a light fit but no appreciable freeplay. Measure the internal diameter of the fork bores and the corresponding diameter of the fork shaft. Renew the forks and/or shaft if they are worn beyond their specifications. Check that the fork shaft holes in the casing are not worn or damaged.

12. The selector fork shaft can be checked for trueness by rolling it along a flat surface. A bent rod will cause difficulty in selecting gears and make the gearchange action heavy. Renew the shaft if it is bent.

30.7b ... and remove the cam locating pin for safekeeping

30.8 Remove the bearing if necessary

30.10 Measuring the selector fork end thickness

2*54 Engine, clutch and transmission

30.16a Assemble the selector forks on the gear pinions ...

13. Inspect the selector drum grooves and selector fork guide pins for signs of wear or damage. If either component shows signs of wear or damage the selector fork(s) and drum must be renewed.

14. Check the selector drum bearing referring to Tools and Workshop Tips (Section 5) in the Reference Section.

Installation

15. If removed, press the selector drum bearing onto the drum. Install the pin in the end of the gear selector drum and install the cam, locating the pin in the cut-out in the back of the cam. Clean the threads of the centre bolt, then apply a suitable non-permanent thread-locking compound. Install the bolt and tighten it to the specified torque setting (see Step 7).

16. Slide the selector forks off their shaft and locate the forks in the grooves in the gear pinions (see Steps 3 and 4) (see illustration). Push the forks forward and slide the selector drum into position in the crankcase (see illustration). Make sure the drum end locates into its bore in the casing, and position it so that the neutral contact is against the neutral switch (see Step 2).

17. Apply a suitable non-permanent thread-locking compound to the selector drum bearing retainer plate bolt, then fit the plate and tighten the bolt securely.

18. Lubricate the selector fork shaft with clean engine oil and slide it through the crankcase and each fork in turn, and into its bore, locating the guide pin on the end of each fork into its groove in the drum as you do (see illustration 30.5b).

19. Apply a suitable non-permanent thread-locking compound to the selector fork shaft retainer plate bolt, then fit the plate and tighten the bolt securely.

20. Lubricate the selector forks and fork grooves with a 50/50 mixture of molybdenum disulphide grease and clean engine oil. Lubricate the gears, shafts and bushings with clean engine oil.

21. Ensure the gears are in the neutral position and check the shafts are free to rotate easily and independently (ie. the input shaft can turn whilst the output shaft is held stationary).